Membrane fusion induced by the envelope glycoproteins of human and simian immunodeficiency viruses (HIV and SIV$_{\text{mac}}$) is a necessary step for the infection of CD4 cells and for the ...formation of syncytia after infection. Identification of the region in these molecules that mediates the fusion events is important for understanding and possibly interfering with HIV/SIV$_{\text{mac}}$ infection and pathogenesis. Amino acid substitutions were made in the 15 NH$_{2}$-terminal residues of the SIV$_{\text{mac}}$ gp32 transmembrane glycoprotein, and the mutants were expressed in recombinant vaccinia viruses, which were then used to infect CD4-expressing T cell lines. Mutations that increased the overall hydrophobicity of the gp32 NH$_{2}$-terminus increased the ability of the viral envelope to induce syncytia formation, whereas introduction of polar or charged amino acids in the same region abolished the fusogenic function of the viral envelope. Hydrophobicity in the NH$_{2}$-terminal region of gp32 may therefore be an important correlate of viral virulence in vivo and could perhaps be exploited to generate a more effective animal model for the study of acquired immunodeficiency syndrome.
Novel strategies for the therapy of recurrent ovarian cancer are warranted. We report a study of a combinatorial approach encompassing dendritic cell (DC)-based autologous whole tumor vaccination and ...anti-angiogenesis therapy, followed by the adoptive transfer of autologous vaccine-primed CD3/CD28-co-stimulated lymphocytes. Recurrent ovarian cancer patients for whom tumor lysate was available from prior cytoreductive surgery underwent conditioning with intravenous bevacizumab and oral metronomic cyclophosphamide, sequentially followed by (1) bevacizumab plus vaccination with DCs pulsed with autologous tumor cell lysate supernatants, (2) lymphodepletion and (3) transfer of 5 × 10
9
autologous vaccine-primed T-cells in combination with the vaccine. Feasibility, safety as well as immunological and clinical efficacy were evaluated. Six subjects received this vaccination. Therapy was feasible, well tolerated, and elicited antitumor immune responses in four subjects, who also experienced clinical benefits. Of these, three patients with residual measurable disease received outpatient lymphodepletion and adoptive T-cell transfer, which was well tolerated and resulted in a durable reduction of circulating regulatory T cells and increased CD8
+
lymphocyte counts. The vaccine-induced restoration of antitumor immunity was achieved in two subjects, who also demonstrated clinical benefits, including one complete response. Our findings indicate that combinatorial cellular immunotherapy for the treatment of recurrent ovarian cancer is well tolerated and warrants further investigation. Several modifications of this approach can be envisioned to optimize immunological and clinical outcomes.
Abstract
BACKGROUND
Standard of care (SOC) and patient survival in glioblastoma have changed little in the past 17 years. We evaluated in a phase 3 trial whether adding an autologous tumor ...lysate-loaded dendritic cell vaccine (murcidencel) to SOC extends survival. Patients and
METHODS
Newly diagnosed glioblastoma patients were randomized 2:1 to either murcidencel or placebo. Under a crossover design, all patients could receive murcidencel following tumor recurrence. All parties remained blinded regarding treatments before recurrence. Patients thus received murcidencel at new diagnosis (nGBM) or at recurrence (rGBM) following crossover from placebo. The primary and secondary endpoints compare overall survival (OS) with contemporaneous, matched external controls. Four sets of analyses were conducted to ensure rigorous matching of the controls, reduce biases, and confirm the robustness of the results.
RESULTS
331 patients were enrolled. With the crossover, 89% received murcidencel. Median OS (mOS) for nGBM patients (n = 232) was 19.3 months from randomization (22.4 months from surgery) with murcidencel vs. 16.5 months from randomization in the controls (HR = 0.80, p = 0.002). Survival at 48 months from randomization was 15.7% vs. 9.9%, and at 60 months was 13% vs. 5.7%. For rGBM (n = 64), mOS was 13.2 months from relapse vs. 7.8 months in the controls (HR = 0.58, p < 0.001). Survival at 24 months post-recurrence was 20.7% vs. 9.6%, and at 30 months post-recurrence was 11.1% vs 5.1%. In nGBM patients with methylated MGMT (n = 90), mOS was 30.2 months from randomization (33 months from surgery) with murcidencel vs. 21.3 months from randomization in the controls (HR = 0.74, p = 0.027). The treatment was well tolerated, with only 5 serious adverse events deemed at least possibly related to the vaccine.
CONCLUSION
Clinically meaningful and statistically significant survival extension was seen in both nGBM and rGBM patients treated with murcidencel and SOC compared with contemporaneous, matched external controls who received SOC alone.
Kaposi's sarcoma—associated herpesvirus (KSHV) in oral and genital secretions of women may be involved in horizontal and vertical transmission in endemic regions. Nested polymerase chain reaction ...assays were used to detect KSHV DNA sequences in one-third of oral, vaginal, and cervical specimens and in 42% of peripheral blood mononuclear cell (PBMC) specimens collected from 41 women infected with human immunodeficiency virus type 1 who had Kaposi's sarcoma (KS). KSHV DNA was not detected in specimens from 100 women without KS, 9 of whom were seropositive for KSHV. A positive association was observed between KSHV DNA detection in oral and genital mucosa, neither of which was associated with KSHV DNA detection in PBMC. These data suggest that KSHV replicates in preferred anatomic sites at levels independent of PBMC viremia. Detection of genital-tract KSHV only among relatively immunosuppressed women may provide an explanation for infrequent perinatal transmission of KSHV.
Background: KSHV, Kaposi’s sarcoma-associated herpesvirus, is a necessary cofactor for the development of Kaposi’s sarcoma (KS). We have previously reported KSHV-related DNA sequences in ...retroperitoneal fibromatosis (RF) tissue from two species of macaque. The putative herpesvirus was called RFHV for RF-associated herpesvirus. These data suggested that KSHV is a human representative of a larger family of primate herpesviruses.
Objective: To identify and characterize other members of a putative family of KSHV-related herpesviruses in macaques in order to obtain information on the evolutionary history of KSHV infection in humans.
Study design: Lymphoid tissue cells and blood leukocytes from rhesus-, cynomolgus- and pigtailed-macaques were tested for the presence of unknown herpesviruses using degenerate primer-driven PCR amplification. The sequences obtained were compared against known herpesvirus sequences.
Results: We have identified new herpesvirus DNA sequences in each of the three macaque species. Sequence comparisons indicate that these new viruses are most related to each other and form a separate phylogenetic lineage within the γ herpesviruses. Screening of PBMC from Indonesian-origin quarantine animals suggests that these viruses (MGV, macaque γ virus) are species-specific, and highly prevalent in the wild. They are readily cultured in vivo, and share a common tissue tropism with the previously identified RFHV.
Conclusions: MGV and RFHV represent two independent introductions of an ancestral γ herpesvirus into macaque precursors.
Standard therapy for glioblastoma includes surgery, radiotherapy, and temozolomide. This Phase 3 trial evaluates the addition of an autologous tumor lysate-pulsed dendritic cell vaccine (DCVax
-L) to ...standard therapy for newly diagnosed glioblastoma.
After surgery and chemoradiotherapy, patients were randomized (2:1) to receive temozolomide plus DCVax-L (n = 232) or temozolomide and placebo (n = 99). Following recurrence, all patients were allowed to receive DCVax-L, without unblinding. The primary endpoint was progression free survival (PFS); the secondary endpoint was overall survival (OS).
For the intent-to-treat (ITT) population (n = 331), median OS (mOS) was 23.1 months from surgery. Because of the cross-over trial design, nearly 90% of the ITT population received DCVax-L. For patients with methylated MGMT (n = 131), mOS was 34.7 months from surgery, with a 3-year survival of 46.4%. As of this analysis, 223 patients are ≥ 30 months past their surgery date; 67 of these (30.0%) have lived ≥ 30 months and have a Kaplan-Meier (KM)-derived mOS of 46.5 months. 182 patients are ≥ 36 months past surgery; 44 of these (24.2%) have lived ≥ 36 months and have a KM-derived mOS of 88.2 months. A population of extended survivors (n = 100) with mOS of 40.5 months, not explained by known prognostic factors, will be analyzed further. Only 2.1% of ITT patients (n = 7) had a grade 3 or 4 adverse event that was deemed at least possibly related to the vaccine. Overall adverse events with DCVax were comparable to standard therapy alone.
Addition of DCVax-L to standard therapy is feasible and safe in glioblastoma patients, and may extend survival. Trial registration Funded by Northwest Biotherapeutics; Clinicaltrials.gov number: NCT00045968; https://clinicaltrials.gov/ct2/show/NCT00045968?term=NCT00045968&rank=1 ; initially registered 19 September 2002.
Active immunotherapy of cancer requires the availability of a source of tumor antigens. To date, no such antigen associated with lung cancer has been identified. We have therefore investigated the ...ability of dendritic cells (DC) to capture whole irradiated human lung tumor cells and to present a defined surrogate antigen derived from the ingested tumor cells. We also describe an in vitro system using a modified human adenocarcinoma cell line (A549-M1) that expresses the well-characterized, immunogenic influenza M1 matrix protein as a surrogate tumor antigen. Peripheral blood monocyte-derived DC, when co-cultured with sub-lethally irradiated A549 cells or primary lung tumor cells derived from surgical resection of non-small cell carcinoma (NSCLC), efficiently ingested the tumor cells as determined by flow cytometry analysis and confocal microscopic examination. More importantly, DC loaded with irradiated A549-M1 cells efficiently processed and presented tumor cell-derived M1 antigen to T cells and elicited antigen-specific immune responses that included IFNgamma release from an M1-specific T-cell line, expansion of M1 peptide-specific Vbeta17+ and CD8+ peripheral T cells and generation of M1-specific cytotoxic T lymphocytes (CTL). We also compared DC loaded with irradiated tumor cells to those loaded with tumor cell lysate or killed tumor cells and found that irradiated lung tumor cells as a source of tumor antigen for DC loading is superior to tumor cell lysate or killed tumor cells in efficient induction of antigen-specific T-cell responses. Our results demonstrate the feasibility of using lung tumor cell-loaded DC to induce immune responses against lung cancer-associated antigens and support ongoing efforts to develop a DC-based lung cancer vaccine.
Although most HIV-1 infections worldwide result from heterosexual transmission, most vaccine candidates have focused on induction of systemic immunity and protection. We hypothesized that combining ...systemic priming with mucosal boosting would induce mucosal immunity that would protect from intravaginal challenge. Macaques were primed systemically with recombinant vaccinia viruses and boosted mucosally using inactivated SHIV89.6 plus adjuvant. Other animals received protein boosts with adjuvant alone. Priming and boosting induced antiviral IgG and IgA antibodies. Such antibodies were induced to a lesser degree in animals receiving boosts alone. Anti-SHIV T cell responses were induced only in the prime-boost animals. Immunized animals and controls were challenged intravaginally with SHIV89.6 and significant reductions in proviral and viral RNA loads were observed in the prime-boost animals. The boost-only animals did not have significant viral load reductions. These data suggest that cellular immunity was required for protection from intravaginal challenge. This immunization regimen provides a promising lead for vaccine development.
Dendritic cells (DC) are acknowledged to be quintessential in the armamentarium to mount anti-tumor immune responses and have been utilized in varying capacities for cancer immunotherapy. Recent ...advancements & lessons leant from prior DC therapies have revealed that major barriers hinder the efficacy of cancer vaccination with DC, principal of which is the hostile environment of the local tumor milieu that inhibits activation and subsequent maturation of DC. This critical step is required to process and present antigens (tumor cell) to the downstream cascade of immune mediators. The therapeutic goals of cancer vaccination are the induction of tumor regression secondary to the production of tumor specific immune factors and local inflammatory cytokines with enhancement of long term anti-tumor surveillance to prevent recurrences. DCVax®- Direct (Northwest Biotherapeutics, Inc. Bethesda, MD) are autologous dendritic cells activated Ex vivo with BCG and IFNγ for intratumoral injection and attempts to circumvent this barrier thereby maximize the induction of anti-tumor responses. Autologous DC will be harvested from peripheral blood monocytes via leukapheresis. Following Ex vivo DC maturation, inoculation of the tumors will be performed 2 weeks later utilizing image guidance to ensure activated DC deposition at the peripheral aspect of the tumor thereby enhancing DC exposure to antigens from dead or dying tumor cells. Vaccination will be performed at least every week for 3 weeks, and subsequently at longer intervals dependent on harvested DC availability. Phase I/II study with DCVax®- Direct will enable evaluation of the safety, MTD, and responses in patients with solid tumors. The secondary objective addresses the feasibility, anti-tumor immune responses, PFS and OS. At the time of this poster submission, the 'First-in-man' patient has been consented for the study. We propose to present our initial findings at the SITC 2013 conference as more data will be available.
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